In general, a photolithography process comprises the steps of applying a photo resist composition on a substrate such as wafer, glass, ceramic, metal, and so on by a spin coating or a roller coating, forming a photo resist layer by heating and drying the applied photo resist composition, forming a photo resist pattern by exposing the photo resist layer to a exposure light of a predetermined pattern, optionally heating, and developing the exposed photo resist layer, and forming a semi-conductor element pattern by etching the substrate with the formed photo resist pattern as a mask. The photolithography process is widely used in production of a semi-conductor such as IC (Integrated Circuit), a LCD (Liquid Crystal Display), photography, and so on.
Due to the increasing demand for the highly integrated semi-conductor device, KrF(248 nm) excimer laser and ArF(193 nm) excimer laser are used as the light source to increase the resolution of a photo resist pattern. In addition, F2 (157 nm) excimer laser, EUV (Extreme Ultra Violet), VUV (Vacuum Ultra Violet), E-beam, X-beam, ion beam, etc have been studied and developed as a light source of a lithography process. However, as being shorter the wavelength of the exposure light, optical interference of the light reflected from the etching layer of the semi-conductor substrate during the exposure process increases. In addition, due to undercutting, notching, etc., the photo resist pattern profile and the uniformity of thickness are deteriorated. To overcome these problems, the bottom anti-reflective coating (BARC) layer is conventionally formed between the etching layer and the photo resist layer to absorb the exposure light. The anti-reflective coating layer can be classified into the inorganic anti-reflective coating layer made of titanium, titanium dioxide, titanium nitride, chrome oxide, carbon, amorphous silicon, and so on, and the organic anti-reflective coating layer made of a polymer, which depends on the material for forming the anti-reflected coating layer. In comparison with the inorganic layer, the organic anti-reflective coating layer does not generally require complex and expensive apparatus such as a vacuum deposition equipment, a chemical vapor deposition (CVD) device, a sputter device and so on for forming the layer, and has a high absorptivity of a radioactive light, and is generally insoluble in a photo resist solvent. Also, small materials thereof does not diffuse from the anti-reflective coating layer into a photo resist layer during coating, heating, and drying the photo resist layer, and the organic anti-reflective coating layer has an excellent etch rate in a dry etch process of a photolithography process. But until now, the conventional composition for forming the organic anti-reflective coating layer is not satisfactory in its characteristics, such as the absorptivity of an exposure light.